1. Section 9.1 Introduction to Stoichiometry
Composition stoichiometry deals with the mass relationships of elements in compounds.
Reaction stoichiometry involves the mass relationships between reactants and products in a chemical reaction.

2. Reaction Stoichiometry Problems
Introduction to Stoichiometry
Reaction Stoichiometry Problems
Problem Type 1: Given and
unknown quantities are amounts
in moles.
Amount of given
substance (mol)
Problem Type 2: Given is an
amount in moles and unknown is
a mass
Amount of given
substance (mol)
Amount of unknown
substance (mol)
Amount of unknown
substance (mol)
Mass of unknown
substance (g)

3. Problem Type 4: Given is a mass and unknown is a mass.
Introduction to Stoichiometry
Problem Type 4: Given is a mass
and unknown is a mass.
Mass of a given substance (g)
Problem Type 3: Given is a
mass and unknown is an amount
in moles.
Mass of given
substance (g)
Amount of given
substance (mol)
Amount of given
substance (mol)
Amount of unknown
substance (mol)
Mass of unknown
substance (g)
Amount of unknown
substance (mol)

4. Mole Ratio
A mole ratio is a conversion factor that relates the amounts in moles of any two substances involved in a chemical reaction
Example: 2Al2O3(l) → 4Al(s) + 3O2(g)
Mole Ratios:
2 mol Al2O3 2 mol Al2O3 4 mol Al
4 mol Al mol O mol O2

5. Converting Between Amounts in Moles

6. Stoichiometry Calculations